LONDON: A dozen Impressionist and post-Impressionist artworks collectively valued at almost half a billion dollars are going up for auction after sitting unseen for decades in a fabled private collection in South America. Sotheby’s auction house said Wednesday that works by Vincent van Gogh and Paul Cézanne are expected to smash records for the artists in the Nov. 18 sale in New York. If so, it would be the latest sign that, in uncertain times, ultrawealthy art collectors are seeking security
